Tri-tert-butyltrihydroxy[3.3.3]metacyclophane 13 was prepared in 6 steps from p-tert-butylanisole in 25% overall yield by using the TosMIC method, followed by Wolff-Kishner reduction and demethylation with boron tribromide. AlC13/ MeN0,-catalyzed trans-tert-butylation of 13 in benzene gave the desired metacyclophane 14 in 85% yield, along with tert-butylbenzene (15). Weak intramolecular hydrogen bonding was observed in the triols 13 and 14. -6,15,24-Tritert-butyl-9,18,2?-trihydroxy[3.3.3]MCP 13 was tri-0-alkylated with alkyl halides (RX: R = Et, Pr, and Bu) in the presence of Cs2C03 to yield partial-cone confomer 12b-d in quantitative yield. Ring inversion by oxygen-through-the-annulus rotation is allowed for triethoxy derivative 12b (coalescence temperature ca. 90 "C) but inhibited for the tripropoxy-1212 and the tributoxy derivative 12d. The reaction of the trio1 13 with ethyl bromoacetate in the presence of Cs2C03 yielded cone and partial-cone 12e, respectively. In contrast, a significant amount of cone conformer 12f resulted when NaH was used as base. Only when the template metal can hold the ester or amide group@) and the oxide group(s) on the same side of the [3.3.3]MCP is the conformation immobilized to the cone. -Titration of cone amide cone-12f with KSCN monitored by IH NMR clearly demonstrates that a 1 : 1 complex is formed which is stable on the NMR time scale, and the original C3 symmetry is retained after the complete metal cation complexation. -The stability of multimembered carbon skeletons permits the interconversion of functional groups without special regard to ring-opening side reactions as was observed for homotrioxacalix [3]arenes with ethereal linkages. For example, the introduction of nitro groups was accomplished on the upper rim by direct threefold ipso-nitration of tert-butyltrimethoxy derivative 12a.

The novel macrocyclic compounds hexahydroxy[1.0.1.0.1.0]-spectra. Methylation of the hydroxyl groups of 6b and 6c with 6b and octahydroxy[l.0.l.0.l.0.l.O]metacyclophane 6c have Me1 gives the corresponding methoxy[l,]metabiphenylobeen prepared in 50-70% yield by base-catalyzed conden-phanes 7b and 7c in good yields. The metacyclophane 7 b has sation of 5,5'-di-tert-butyl-2,2'-dihydroxybiphenyl (5) with been found to consist of two isomers, out of which one was formaldehyde in xylene. The conformations of trimer 6b and separated pure. The structural characterization of these prodtetramer 6c have been evaluated from their dynamic 'H-NMR ucts is discussed.Due to their importance in supramolecular chemistry['] a large variety of macrocyclic compounds such as crown ethersL2], cryptatesF3], cyclophane~~~~, and spherandsF5I have been synthesized and their properties investigated. Our present work is directly related to the studies of Cram and his co-workersF5] in designing spherands possessing 1,l'-biarene units (e. g. 1) which contain enforced, spherical cavities lined with electron pairs of heteroatoms so that upon complexation with metal ions no conformational rearrangement is possible.Closely related to the spherands are the "calixarenes", [l,]metacyclophanes (example 2a), prepared by base-catalyzed condensation of p-substituted phenols with formaldehyde[6a1. These are attractive building blocks, their phenolic hydroxyl groups being ordered in well-shaped cyclic arraysF6] which can be f~nctionalized~'~ to give novel guest inclusion blocks. The combination of structural elements of both spherands and calixarenes is expected to lead to novel macrocyclic compounds, which may be highly stimulating for future work in the field of host-guest chemistry.Recently, we have demonstrated a convenient synthesis of the propane-bridged calixareneanalogs of metacyclophanes such as tetrahydroxy (83%) 5 We describe in this paper the first example of the synthesis of a series of hydroxy[l,]metabiphenylophanes with three and four biarene units, 6, and their methoxy derivatives 7, derived from 5,5'-di-tert-butyl-2,2'-dihydroxybiphenyl (5). These compounds are expected to have combined properties of both the spherands and the calixarenes.The starting compound 5['] was prepared in two steps from 2,4-di-tert-butylphenol (3) by using the tert-butyl group as a positional protective group on the aromatic ring [9 -131When 5 was treated with paraformaldehyde in refluxing xylene under basic conditions['41, the expected products 4,10,17,23,30,36-hexa-twt-butyl-7,13,20,26,33,39-hexahydroxy-

Speciation determines toxicity, transport pathways and residence time of a metal in different compartments of the environment. This study investigated the speciation of mercury in soils, derived from sites known for dumping of mine wastes in the Bibiani-Anwiaso-Bekwai district, a gold mining community of the Western Region of Ghana. Soil samples were taken from the surface; depths of 20, 40 and 60 cm from mine waste at both abandoned and active mine sites. Each sample was analysed for total mercury, organic mercury and elemental mercury. After sample treatment, digestion and reduction with stannous chloride (SnCl(2)), total mercury content was determined using the Inductively Coupled Plasma-Optical Emissions Spectrometer (ICP-OES). Organic mercury content was determined employing a differential technique after disposing of elemental mercury by heating. Total mercury content in samples ranged from 0.067 to 0.876 mg/kg for surface soils. The same soil of depths 20, 40 and 60 cm had total mercury from 0.102 to 1.066, 0.037 to 4.037 and 0.191 to 4.998 mg/kg, respectively. For organic mercury, concentrations range from 0.012 to 0.260 mg/kg for surface soil. Soil depths of 20, 40 and 60 cm had organic mercury concentrations from 0.016 to 0.653, 0.041 to 1.093 and 0.101 to 2.546 mg/kg respectively. Elemental mercury concentrations in surface soils, soils at depths of 20, 40 and 60 cm ranged from 0.043 to 0.780; 0.017 to 0.749; 0.014 to 2.944 and 0.009 to 2.452 mg/kg respectively. Among the sites studied, only galamsey tailings (GM) showed a trend of increasing total mercury level with increasing depth. For the other sites, trends were not defined. There has been no defined trend for elemental mercury with depth at any of the sampling sites. Just as with total mercury, it was only GM that showed an increasing trend of organic mercury concentration with depth.

Artisanal gold mining in local communities is on the increase. This has led to concerns about mercury pollution resulting from these mining activities. This study was conducted to assess the level of mercury pollution in rivers and streams around artisanal gold mining areas of the Birim North District of Ghana. Rivers, streams, sediments and boreholes were sampled to determine total mercury levels during the wet and dry seasons and to explore the potential impact of the mercury levels on water quality in the area. The results show that the total mercury concentrations measured upstream were significantly lower than concentrations in samples taken downstream. Also, the total mercury concentrations measured in the stream water samples in both seasons exceeded the WHO guideline limit (1.0 µg/L) for drinking water. However, one downstream total mercury concentration exceeded the guideline limit in the dry season. The total mercury concentrations in sediments upstream and downstream in both seasons exceeded the US-EPA guideline value of 0.2 mg/kg. The boreholes in the study area have total mercury concentrations exceeding the WHO guideline limit during both seasons. Total mercury concentrations in the boreholes in the wet season were lower than the dry season

Hydroxy[3.1.1]rnetacyclophane 4c, which is regarded as an unsymmetric or uncomplete "homocalixarene " bearing a propane bridge, has been synthesized using Nafion-H catalyzed cyclobenzylation. A novel "pendulum" type motion steered by intramolecular hydrogen bonding has been observed. Demethylation of compound 4c with BBr3 in methylene dichloride was carried out at room temperature for 3 h to afford the dihydroxy[3.l.l]metacyclophane 4b in 74% yield along with the trio1 4a in 25% yield. Trio1 4a was tri-0-alkylated with methyl iodide in the presence of NaH to yield partial-cone conformer 4d in quantitative yield. Similarly, a significant amount of partial-cone conformer 5 results in the case of 0-alkylation of 4a with N,N-diethylchloroacetamide. 'H-NMR titration of partial-cone amide 5 with NaSCN clearly demonstrates that a 1:1 complex is formed which is stable on the NMR time scale.